Coating film forming method and coating film forming apparatus

Abstract

A coating film forming method for forming a resist coating film on an upper surface of a wafer held by a spin chuck in a chamber includes (a) the step of keeping preliminary correlation data representing correlation between a wafer rotating speed and the thickness of the resist coating film formed on the wafer in the chamber, (b) the step of conveying the wafer into the chamber and holding the wafer by the spin chuck, (c) the step of pouring the resist liquid onto the wafer and spin-rotating the wafer to form a resist coating film on the upper surface of the wafer, (d) the step of detecting the thickness of the formed resist coating film by a sensor, (e) the step of detecting a rotating speed of the spin chuck by a sensor, and (f) the step of, on the basis of the detected film thickness and the preliminary correlation data, correcting a set rotating speed of the spin chuck to feedback-control a resist coating process for a next wafer.

We claim: 
     
       1. A coating film forming method for forming a resist coating film on an upper surface of a substrate held by a spin chuck in a chamber to which a downflow of clean air is supplied, comprising: (a) the step of keeping preliminary correlation data representing correlation between a rotating speed of said substrate, a temperature of at least one of a resist liquid to be coated and the upper surface of said substrate, and the thickness of the resist coating film formed on said substrate in said chamber;   (b) the step of conveying said substrate into said chamber and holding said substrate by said spin chuck;   (c) the step of pouring the resist liquid onto said substrate and spin-rotating said substrate to form a resist coating film on the upper surface of said substrate;   (d) the step of detecting the thickness of the resist coating film formed on the upper surface of said substrate by film thickness detection means;   (e) the step of detecting a rotating speed of said spin chuck by rotating speed detection means, and of detecting a temperature of at least one of the resist liquid to be coated and the upper surface of the substrate by temperature detections means; and   (f) the step of, on the basis of the detected film thickness, the detected rotating speed, the detected temperature of at least one of the resist liquid to be coated and the upper surface of the substrate, and the preliminary correlation data, correcting a set rotating speed of said spin chuck to feedback-control a resist coating process for a next substrate.   
     
     
       2. A method according to claim 1, wherein the step (e) further comprises the step of detecting the temperature of the resist liquid immediately before the resist liquid is coated on said substrate; and the step (f) further comprises the step of correcting the temperature of a resist liquid to be coated on a next substrate on the basis of the detected temperature, the detected film thickness, and the preliminary correlation data.   
     
     
       3. A method according to claim 1, wherein the step (e) further comprises the step of detecting the temperature of the upper surface of said substrate immediately before a resist liquid is coated on said substrate; and   the step (f) further comprises the step of correcting the temperature of an upper surface of a next substrate on the basis of the detected temperature, the detected film thickness, and the preliminary correlation data.   
     
     
       4. A method according to claim 1, wherein after the resist coating film is heated by baking and then cooled, the thickness of the resist coating film is measured in the film thickness detection step (d).   
     
     
       5. A method according to claim 1, wherein the thickness of the resist coating film is detected in said chamber in the step (d), on the basis of the detection information, thicknesses of resist coating films on subsequent substrates are sequentially controlled.   
     
     
       6. A method according to claim 1, wherein in the step (d), thicknesses of the resist coating film at a plurality of positions while said substrate on said spin chuck and said thickness detection means are relatively moved.   
     
     
       7. A method according to claim 1, wherein the thickness of the resist coating film in the step (d) is measured each time resist coating is performed to twenty-five substrates of one lot.   
     
     
       8. A method according to claim 1, wherein the thickness of the resist coating film in the step (d) is measured each time resist coating is performed to each substrate.   
     
     
       9. A method according to claim 1, wherein an atmosphere in said chamber is controlled before the step (c) to adjust an atmosphere around said substrate on said spin chuck to an atmosphere suitable for a resist coating process.   
     
     
       10. A coating film forming method for forming a resist coating film on an upper surface of a substrate held by a spin chuck in a chamber to which a downflow of clean air is supplied, comprising: (A) the step of keeping primary correlation data representing correlation between a rotating speed of a dummy substrate rotated by said spin chuck, a temperature of at least one of a resist liquid to be coated and the upper surface of the substrate, and the dummy thickness of the resist coating film formed on said substrate in said chamber;   (B) the step of conveying said product substrate into said chamber and holding said product substrate by said spin chuck;   (C) the step of pouring the resist liquid onto said product substrate and spin rotating said product substrate to form a resist coating film on the upper surface of said product substrate;   (D) the step of detecting the thickness of the resist coating film formed on the upper surface of said product substrate by film thickness detection means;   (E) the step of detecting the rotating speed of said spin chuck by rotating speed detection means, and of detecting a temperature of at least one of the resist liquid to be coated and the upper surface of the substrate by temperature detection means; and   (F) the step of, on the basis of detected film thickness, the detected rotating speed, the detected temperature of at least one of the resist liquid to be coated and the upper surface of the substrate, and the preliminary correlation data, correcting a set rotating speed of said spin chuck to feedback-control a resist coating process for a next product substrate.   
     
     
       11. A method according to claim 10, wherein the step (E) further comprises the step of detecting the temperature of the resist liquid immediately before the resist liquid is coated on said product substrate; and   the step (F) further comprises the step of correcting the temperature of a resist liquid to be coated on a next product substrate on the basis of the detected temperature, the detected film thickness, and the preliminary correlation data.   
     
     
       12. A method according to claim 10, wherein the step (E) further comprises the step of detecting the temperature of the upper surface of said product substrate immediately before a resist liquid is coated on said product substrate; and   the step (F) further comprises the step of correcting the temperature of an upper surface of a next product substrate on the basis of the detected temperature, the detected film thickness, and the preliminary correlation data.   
     
     
       13. A method according to claim 10, wherein after the resist coating film is heated by baking and then cooled, the thickness of the resist coating film is measured in the film thickness detection step (D).   
     
     
       14. A method according to claim 13, wherein after the thickness of the resist coating film formed on said dummy substrate is detected, the resist coating film is removed from said dummy substrate, and said dummy substrate is used in the step (A) again to keep another preliminary correlation data.   
     
     
       15. A method according to claim 10, wherein after the thickness of the resist coating film formed on said dummy substrate is detected, the resist coating film is removed from said dummy substrate, and said dummy substrate is used in the step (A) again to keep another preliminary correlation data.   
     
     
       16. A method according to claim 10, wherein an atmosphere in said chamber is controlled before the step (C) to adjust an atmosphere around said substrate on said spin chuck to an atmosphere suitable for a resist coating process.   
     
     
       17. A method according to claim 10, wherein the thickness of the resist coating film in the step (D) is measured each time resist coating is performed to twenty-five substrates of one lot.   
     
     
       18. A method according to claim 10, wherein the thickness of the resist coating film in the step (D) is measured each time resist coating is performed to each substrate.   
     
     
       19. A method according to claim 10, wherein in the step (D), thicknesses of the resist coating film at a plurality of positions while said substrate on said spin chuck and said thickness detection means are relatively moved.   
     
     
       20. A coating film forming apparatus for supplying a resist liquid onto an upper surface of a substrate and spin-rotating said substrate to form a resist coating film on the upper surface of said substrate, comprising: a chamber to which a downflow of clean air is supplied;   a spin chuck, arranged in said chamber, for holding said substrate;   rotational driving means for spin-rotating said spin chuck;   resist liquid supply means for supplying the resist liquid to said substrate on said spin chuck;   a film thickness sensor, arranged in said chamber, for detecting the thickness of a resist coating film formed on the upper surface of said substrate;   at least one of a first temperature sensor for detecting a temperature of the resist liquid and a second temperature sensor for detecting a surface temperature of the substrate;   at least one of first temperature adjustment means for adjusting the temperature of a resist liquid to be coated on said substrate and second temperature adjustment means for adjusting the surface temperature of the substrate; and   control means for controlling said rotational driving means on the basis of a film thickness detection signal from said film thickness sensor, and for controlling said first temperature adjustment means on the basis of a temperature signal supplied from said first temperature detector and the film thickness signal supplied from said film thickness sensor, and for controlling said second temperature adjustment means on the basis of a surface temperature signal supplied from said second temperature sensor and the film thickness signal supplied from said film thickness sensor.   
     
     
       21. An apparatus according to claim 20, further comprising third temperature adjustment means for adjusting the temperature of a dummy substrate used to keep preliminary correlation data representing correlation between the temperature of said dummy substrate and the thickness of a resist coating film to be formed on said substrate.   
     
     
       22. An apparatus according to claim 21, further comprising solvent supply means for pouring a solvent for removing the resist coating film formed on the upper surface of said dummy substrate onto said dummy substrate.   
     
     
       23. An apparatus according to claim 20, further comprising a rotating speed detection sensor for detecting a rotating speed of said spin chuck.